Adjustable motion transmission



March 24, 1942. c. E. M. BUTLER 2,277,632

ADJUSTIBLE MOTION TRANSMiSSION MECHANISM FOR AN ALTIMETER OR THE LIKE Filed April 25, 1941 Patented Mar. 24, 19 42 ADJUSTABLE MOTION FOR ALTIMETERS OR MECHANISM THE LIKE TRANSMISSION Charles Edward Meyer Butler, London, Engl land, assignor to S. Smith & Sons (Motor Accessories) Limited, London, England, a

British company Application April 25, 1941, Serial No. 390,382 In Great Britain March 4, 1940 8 Claims.

This application corresponds to the application of S. Smith & Sons (Motor Accessories) Limited and Charles Edward Meyer Butler, Serial No. 4,039/40, which was filed in Great Britain on March 4, 1940.

This invention relates to apparatus comprising mechanism of a delicate character such for instance as is employed in'instruments to transmit movement of an operating element to an in-' dicating pointer or the like and is concerned tive altimeter in which the manual control member provides for the adjustment of the indicating pointer or the like of the altimeter'in relation to the operating barometric capsule.

In the accompanying drawing there is shown by way of example an embodiment of the invention applied to a sensitive altimeter, and in the drawingwith such apparatus of the kind in which a Y manual control member is carried by a casing of the mechanism for adjustment of the mechanism, for instance, in order to set the pointer in relation to the device which operates it.

To avoid transmitting shocks to the mechanism through the handling of the manual control and also to economise in space in the casing of the mechanism it is'known to mount. the manual control separately in a recess in the casin so that it meshes with an element of the mechanism to provide the necessary adjustment. This construction has the disadvantage that the easing has to be accurately made to ensure correct meshing between an adjusting gear and a 00- operating gear of the mechanism, and the present invention is directed towards overcoming this difficulty.

According to the present invention there is provided an apparatus of the kind specified wherein the manual control member carried by the casing is coupled to the mechanism through a gear which is rotatable on a frame or bracket Figure 1 is arr-elevation partly in section of the altimeter;

Figure 2 is a detail cross-section on an enlarged scale of the manual control, and

Figure 3 is a section on line 3-3 of Figure 2. Referring to the drawing, the instrument comprises a casing l0, which may for example be constructed of a material such as that known under the registered trade-mark Bakelite, and

which houses the mechanism of the instrument.

- The mechanism comprises a barometric capsule is connected by step-up gearing, to indicating pivoted on the casing so that the frame may be swing to bring the gear into correct mesh with a co-operating gear of the mechanism. In this way, it is unnecessary to provide for accurate construction of the casing to ensure, that the manual control member carried by it properly meshes/with the mechanism. Means is preferably provided for holding the frame in its position of adjustment providing correct mesh of the gears and such means may comprise a tongue or tongues on the frame bendable to' engage with the casing or other fixed part within the casing In a preferred construction the gear carried by the frame aforesaid meshes with a co-operating gear which may-either be a driving or a driven gear which is mounted for rotation about the pivotal axis of the frame. In this construction it is convenient for the said co-operating gear to be a driving gear fixed to the manual control member. i

One application of the invention is to a sen'si- H carried by a frame l2, the movable part of v which capsule is connected by a link l3 to a crank H on a rotatable spindle IS. The rotation of the spindle is transmitted by means of a crank IS on this spindle and a link I! connecting the crank to another crank III on a spindle 20 which pointers (not shown). This step-up gearing consists of a gear 2| fixed to the spindle 20 and meshplate 25 about this axis the indicating pointers meshing with a gear 3| which is rotatable on the Y are rotated for adjustment in relation to the normal indicating drive actuated by the movable part of the barometric capsule H.

For the adjustment of the altimeter there is provided a manual control knob 26 carried on a spindle 21 which is rotatably mounted in the casing [0. On the spindle 21 there ispivoted a frame consisting of end plates 28 joined by a stud 29 so that this frame can swim about the spindle 21. The spindle carries a pinion 30 stud 29. This gear 3| is .in driving connection with another gear 32 also rotatable on the stud 29. In assembling the instrument in the casing the frame is turned so that the gear on the frame is brought correctly into mesh with another gear 33 carried by the frame of the instrument. This gear 33 forms part of atrain of gears for rotating a cam 34 acting on an extension 35 of the plate 25' so as toturn this plate against the action of a loading spring (not shown) for the adjustment of the altimeter.

After the frame has been positioned to correctly mesh the gears 32 and 33 tongues 38 on the plates 28 of the frame are bent to engage a convenient part of the casing so as to hold the gears 32 and 33 correctly in mesh. It will be seen therefore that the position of the spindle 21 whichv is governed by the construction of the casing need not be accurate with respect to the gear 33 which is carried by the frame of the instrument and that any inaccuracies within wide'limits can be made good by the adjustment of the frame which carries the gear-32..

The gears 3| and 32 on the stud 29 are coupled by means of an over-riding or slippingclutch in order to prevent any undue strain being placed on the mechanism by turning of the manual control knob 26. This clutch consists of V-shaped indicator or the like, which device includes a casing, a transmission mechanism in said casing .and operatively connecting said instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing or receding the position of the second instrumentality with-respect to the'primary instrumentality, as for effecting a correction in an indicator setting: apparatus for moving said adjusting. gear at will, said apparatus including a manually movable control member carried by the casing, a bracket pivoted to said casing and adapted to swing toward and from said adjusting gear, a gear carried by said bracket to be brought into mesh with said adjusting gear when the bracket is swung toward the latter, and operative driving connections between said manual control member and the second named gear.

2. In a device for repeating or proportionately reproducing the movements of a primary instrumentality in a second instrumentality such as an indicator or' the like, which device includes V a casing,'a transmission mechanism in said casing and operatively connecting said instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing or receding theposition of the second instrumentality with respect to the primary instrumentality, as for effecting a correction in an indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manually movable control member carried by thecasing, a frame pivoted to said casing and adapted to swing toward and from said adjusting gear, a gear carried by said frame to be brought into mesh with said adjusting gear when the frame is swung toward the latter, operative driving connections between said manual control member and the second named gear and means for maintaining the frame in a fixed position wherein the second named gear is in correct meshing engagement with said adjusting gear. I

advancing or receding the position of the second instrumentality with respect to the primary instrumentality, as effecting a correction in an indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manually movable control member carried by the casing, a frame pivoted to said casing and adapted to swing toward and from said adjusting gear, a gear carried by said frame to be brought into mesh with said adjusting gear when the frame is swung toward the latter, operative driving connections between said manual control memher and the second named gear and means for maintaining the frame in a fixed position wherein the second named gear is in correct meshing engagement with said adjusting gear, said last named means comprising 'a tongue on the frame bendable to engage with a part fixed with respect to said casing;

4. In a device for repeating or proportionately reproducing the movements of a primary instrumentality in a second instrumentality such as an indicator or the like, which device includes a casing, a transmission mechanism in said casing and operatively connecting said instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing or receding the position of the second instrumentality with respect to the primary in-: strumentality, as for effecting a correction inan indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manual control member carried by the casing for adjusting said mechanism through the adjusting gear, a bracket pivotally mounted on the casing, a driving gear coupled to said manual control and rotatable about the pivotal axis of the bracket, and an intermediate gear rotatable on the bracket and meshing with said driving gear, which bracket is movable about the pivotal mounting thereof to bring the intermediate gear into correct mesh with the said adjusting gear.

5. In a device for repeating or proportionately reproducing the movements of a primary instrumentality in a second instrumentality such as an indicator or the like, which device includes a casing, a transmission mechanism in said casing and operatively connecting instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing or receding the position of the second instrumentality with respect to the primary instrumentality, as for effecting a correction in an indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manual control member rotatably carried by the casing, a driving gear fixed to the control member and rotatable therewith, a bracket pivotally mounted on the casing about the axis of the driving gear her and the second named gear.

7. In a device for repeating or proportionately reproducing the movements of a primary instrumentality in a second instrumentality such as an indicator or the like, which device includes a casing, a transmission mechanism in said casing and operatively connecting said instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing and receding the position of the second instrumentality with respect to the primary instrumentality, as for efiecting a correction in an indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manual control member rotatably carried by the casing, a driving gear fixed to the control member and rotatable therewith, a bracket pivotally mounted on the casing about the axis of the driving gear and an intermediate gear rotatable on the bracket and meshing with said driving gear, which bracket is movable about its pivotal mounting to bring the intermediate gear into correct mesh with the said adjusting gear.

8. In a device for repeating or proportionately reproducing the movements of a primary instrumentality in a second instrumentality such as an indicator or the like, which device includes a casing, a transmission mechanism in said casing and operatively connecting said instrumentalities, and a rotatable adjusting gear operatively connected in said transmission mechanism for advancing or receding the position of the second instrumentality with respect to the primary instrumentality, as for effecting a correction in an indicator setting: apparatus for moving said adjusting gear at will, said apparatus including a manually movable control member carried by the casing, a bracket pivoted to said casing and adapted to swing toward and from said adjusting gear, a gear carried by said bracket to be brought into mesh with said adjusting gear when the bracket is swung toward the latter, and a yielding driving connection between said manual control member and the second named gear.

CHARLES EDWARD MEYER BUTLER. 

